Not Applicable
The present invention is related to the field of sensors and sensor systems used in analyzing the gait of a patient or other subject.
There has been a dramatic increase in the incidence of foot-related illnesses and other maladies that manifest themselves in a person""s gait, and an attendant increase in the number of consultations with podiatrists and other medical professionals who deal with such medical problems. In an increasingly common scenario, a patient who visits a podiatrist is asked a series of questions about his problem, and an examination is performed, which typically includes observing the patient""s gait during a brief walk. Oftentimes, after a possibly tentative diagnosis is reached, an orthotic device is prescribed. The patient returns for an additional office visit after the orthotic is made, and the orthotic is custom-fitted by the podiatrist. There may be one or more follow-up visits to determine whether the orthotic is achieving the desired results.
Current procedures like those described above can be excessively time-consuming, and tend to rely excessively on trial and error. Additionally, the patient feedback for prognosis purposes is very subjective. Thus, there has been a need for more objective techniques for gait analysis in the diagnosis, treatment and prognosis of podiatric illnesses.
Recently, gait analysis systems have been deployed that bring a desired measure of objectiveness to the diagnosis and treatment of podiatric illnesses. One such system utilizes a special shoe that is worn by a patient during an office visit. The footbed of the shoe contains a large number of small pressure sensors that generate electrical output signals indicative of pressure in a small area surrounding the sensor. These sensors are connected to a rather large data collection and analyzing system, using a lengthy cable harness with a number of wires carrying the sensor signals. The data analysis system is responsible for collecting data from the sensors at a given sampling rate while the patient takes a few steps, and then performs various signal processing on the large quantity of collected data in order to present diagnostically useful information to the physician using the system.
Gait analysis systems such as the one described above are considerably expensive, partly due to their use of numerous sensors and the attendant size of the data collection and signal processing tasks. In addition, because the patient is xe2x80x9ctetheredxe2x80x9d to the system by the cable harness during use, such systems tend to be awkward to use, and are prone to cable-related malfunction. Moreover, the tethering can interfere with the analysis by artificially restricting the movement of the patient. Accordingly, there has been a need for improved gait analysis systems.
In accordance with the present invention, a gait analysis system is disclosed that improves upon the above-mentioned drawbacks of present systems. The disclosed system includes a shoe insert configured for use in a shoe to be worn by a subject while walking as part of a process of collecting gait data. The shoe insert has a small number of force-sensing sensors distributed in a manner defining a sensing aperture. Each sensor provides an electrical output signal. Processing apparatus is communicatively coupled with the sensors on the shoe insert. The processing apparatus is operative to calculate a gait line that is represented by a series of points, wherein each point is calculated as a spatially-weighted average of samples of the sensor output signals over the sensing aperture.
In one embodiment, the processing apparatus includes a portable telemetry transmitter worn by the subject during the data collection process. The transmitter is connected to the sensors to receive the sensor output signals, and transmits a radio signal carrying the sensor information. A stationary receiver receives the sensor information in a transmission from the transmitter, and provides the sensor information to a personal computer or similar workstation. The use of a portable transmitter greatly enhances the usefulness of the system, by enabling the subject to walk in a normal manner unimpeded by electrical cables or other apparatus.
Other aspects, features, and advantages of the present invention are disclosed in the detailed description that follows.